The present invention relates to devices for expediting the healing of bone or soft tissue fractures or other defects in a patient, and more particularly to devices for applying traction and at the same time flexing the joint or joints adjacent the injured area.
It has long been known to place fractures, particularly comminuted fractures, under distal traction. Otherwise, compressive forces exerted on the healing bone will tend to collapse the bone. Patients with fractured leg or arm bones may lie in bed with their broken limbs tractioned to devices at the ends of their beds. For healing comminuted finger bones (phalanges), portable devices are in use which are attached to the arm and which hold the finger immobilized under distal traction.
One noted consequence of bone fracture and the subsequent healing process is stiffness of joints and deterioration of cartilage tissue in the joints to which the fractured bone is connected, particularly the joint immediately proximal to the fractured bone. There is good medical evidence to suggest that the cartilage deterioration is, to a significant degree, a result of extended immobilization of the joints.
A number of recent studies relating to joint disorders suggest the value of subjecting injured or diseased joints to passive motion, which preferably is continuous. For example, Robert Salter et al., "The Biologic Effect of Continuous Passive Motion on the Healing of Full Thickness Defects in Articular Cartilage", Journal of Bone and Joint Surgery, 62-A:1232-1251, 1980, describes the beneficial effects of continuous passive motion on healing of cartilage defects with apparently normal hyaline and cartilage. Richard H. Gelberman, et al., The Journal of Bone and Joint Surgery, 65A, pp. 70-80 (1983) describe the benefits of controlled motion in flexor tendon healing and restoration. As a result of such studies, various devices have been proposed to provide passive motion to damaged or diseased joints. Recently, devices have become available for continuously flexing and extending phalangeal joints for joint healing and joint therapy. One example of such a device is sold by Sutter Biomedical, Inc. Another such device is sold by Toronto Medical Corp. under the tradename "Mobilimb". Although both of these devices have advantages for joint therapy and promote healing of damaged or diseased joints, they do not place the phalanges under traction in the manner desired for healing fractures and are generally unsuitable for the treatment of unstable phalangeal fractures. The Toronto Medical Corp. specifically notes in its product information literature that its unit is contraindicated for unstable fractures.
Devices which apply traction to or adjacent the joint are often connected in a manner which does not permit application of substantial traction force to the joint. For example, an attachment glued to a fingernail may pull out the fingernail when highly tractioned. Other attachments to fingers, or the like, pull off or do not apply the traction force sufficiently directly to the joint.
It is a primary object of the present invention to provide motion to joints that are proximally adjacent to fractures, and at the same time, to apply traction to the fractured bone or soft tissue while the joint is in motion.